Just FYI, there is no need to add ESXi to your AD, if you use vCenter that will take care of this for you.. vCenter will need to be added to AD, but ALL hosts managed by vCenter will not.
If you want to login as AD user on each ESXi host, that's different.. but if you have vCenter these steps are not necessary... The problem I have with ESXi sometimes it loses its connection, and I have to remove \ re-add to domain.